ASP.NET MVC XML绑定Action参数列表

昨天查看了 ASP.NET MVC 的生命周期，并没有找到类似的解决方案。

不过今天在 stackoverflow上找到了解决方案，没耐心的同学可以直接戳原文拷贝代码，原文地址：How to pass XML as POST to an ActionResult in ASP MVC .NET

看了外国同学的说明，才发现 MVC居然可以根据不同的请求 Content Type来选择 ValueProvider，这样提供了很好的扩展。

MVC本身提供了 JsonValueProviderFactory，顾名思义就是为 Json服务的。那么在这里我们需要提供为 XML服务的ValueProviderFactory。

第一步：创建 XMLValueProviderFactory

public class XmlValueProviderFactory : ValueProviderFactory
    {
        private static void AddToBackingStore(Dictionary<string, object> backingStore, string prefix, XElement xmlDoc)
        {
            // Check the keys to see if this is an array or an object
            var uniqueKeys = new List<string>();
            int totalCount = 0;
            foreach (XElement element in xmlDoc.Elements())
            {
                if (!uniqueKeys.Contains(element.Name.LocalName))
                    uniqueKeys.Add(element.Name.LocalName);

                totalCount++;
            }

            bool isArray;
            if (uniqueKeys.Count == 1)
            {
                isArray = true;
            }
            else if (uniqueKeys.Count == totalCount)
            {
                isArray = false;
            }
            else
            {
                // Not sure how to deal with a XML doc that has some keys the same, but not all
                // For now don‘t process this node
                return;
            }

            // Add the elements to the backing store
            int elementCount = 0;
            foreach (XElement element in xmlDoc.Elements())
            {
                if (element.HasElements)
                {
                    if (isArray)
                    {
                        // Omit local name for arrays and add index instead
                        AddToBackingStore(backingStore, $"{prefix}[{elementCount}]", element);
                    }
                    else
                    {
                        AddToBackingStore(backingStore, MakePropertyKey(prefix, element.Name.LocalName), element);
                    }
                }
                else
                {
                    backingStore.Add(MakePropertyKey(prefix, element.Name.LocalName), element.Value);
                }

                elementCount++;
            }
        }

        private static XDocument GetDeserializedXml(ControllerContext controllerContext)
        {
            var contentType = controllerContext.HttpContext.Request.ContentType;
            if (!contentType.StartsWith("text/xml", StringComparison.OrdinalIgnoreCase)
                && !contentType.StartsWith("application/xml", StringComparison.OrdinalIgnoreCase))
            {
                // Are there any other XML mime types that are used? (Add them here)

                // not XML request
                return null;
            }

            XDocument xml;
            try
            {
                // DTD processing disabled to stop XML bomb attack - if you require DTD processing, read this first: http://msdn.microsoft.com/en-us/magazine/ee335713.aspx
                var xmlReaderSettings = new XmlReaderSettings {DtdProcessing = DtdProcessing.Prohibit};
                var xmlReader = XmlReader.Create(controllerContext.HttpContext.Request.InputStream, xmlReaderSettings);
                xml = XDocument.Load(xmlReader);
            }
            catch (Exception)
            {
                return null;
            }

            if (xml.FirstNode == null)
            {
                // No XML data
                return null;
            }

            return xml;
        }

        private static string MakeArrayKey(string prefix, int index)
        {
            return prefix + "[" + index.ToString(CultureInfo.InvariantCulture) + "]";
        }

        private static string MakePropertyKey(string prefix, string propertyName)
        {
            return (prefix.IsNullOrEmpty()) ? propertyName : prefix + "." + propertyName;
        }

        #region ValueProviderFactory Members

        public override IValueProvider GetValueProvider(ControllerContext controllerContext)
        {
            var xmlData = GetDeserializedXml(controllerContext);
            if (xmlData == null)
                return null;

            var backingStore = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
            AddToBackingStore(backingStore, String.Empty, xmlData.Root);
            return new DictionaryValueProvider<object>(backingStore, CultureInfo.CurrentCulture);
        }

        #endregion
    }

该段代码属于网上抄袭，基本没有改，在下觉得这样已经满足需求了，原文地址：Sending XML to an ASP.NET MVC Action Method Argument

PS：如果涉及版权问题，请告知在下。

第二步：在 Global.asmx.cs 的 Application_Start 方法中注册 ValueProviderFactory

ValueProviderFactories.Factories.Add(new JsonValueProviderFactory());
ValueProviderFactories.Factories.Add(new XmlValueProviderFactory());

亲测可用，如有问题，请留言。